This invention relates to a radial piston machine, such as a pump or motor.
Radial piston machines are well known in the art and are, therefore, not considered to require a detailed description as to their operation. It is known that the pressure acting on the cylinder bores of the rotor, which are located at the high-pressure side, presses the rotor against the mounting shaft in the area of the high-pressure fluid control opening. This force is opposed by pressure fields which develop in the gap between the shaft and the rotor, above the sealing lands and supporting lands in the region of the high-pressure control opening; it is also opposed by the force which acts above the high-pressure control opening upon the rotor.
Depending upon the dimensioning of the sealing lands and the supporting lands, and of the high-pressure control opening, the forces of the pressure fields which tend to lift the rotor body off the shaft may be greater than the force pressing it against the shaft. If this occurs, the rotor will contact the shaft in the region of the low-pressure fluid control opening with a consequent enlargement of the space between the shaft and rotor in the region of the high-pressure control opening, and with a concomitant undesirable increase in leakage losses.